Typically natural gas transmission pipelines operate at pressures ranging between 700 and 1500 psia. Natural gas pressure reduction points are often referred to as let-down stations. Such stations enable the regional distribution of natural gas (typically at pressures of 150 to 500 psia). In general, let-down stations are not designed for the useful recovery of the pressure energy. Processes which serve to let-down natural gas while producing a fraction of the inlet gas as liquefied natural gas are often referred to as expander cycles or expander plants.
It is an object of this invention to provide an improved method for employing pressure energy to produce liquefied natural gas.